swc-plugin-transform-import

Inspired from babel-plugin-transform-imports

Installation

npm i -D swc-plugin-transform-import

Uses with webpack-config

// webpack.config.js

const PluginTransformImport = require('swc-plugin-transform-import').default;

module: {
    rules: [
      {
        test: /\.(ts|tsx|js|jsx)$/,
        exclude: /node_modules/,
        use: [{
          loader: 'swc-loader',
          options: {
            plugin: (m) => new PluginTransformImport({
              "lodash": {
                "transform": "lodash/${member}",
                "preventFullImport": true
              }
            }).visitProgram(m),
          }
        }]
      },
    ],
};

import { Row, Grid as MyGrid } from 'react-bootstrap';
import { merge } from 'lodash';

...into default style imports:

import Row from 'react-bootstrap/lib/Row';
import MyGrid from 'react-bootstrap/lib/Grid';
import merge from 'lodash/merge';

Note: this plugin is not restricted to the react-bootstrap and lodash libraries. You may use it with any library.

That's stupid, why would you do that?

When SWC encounters a member style import such as:

import { Grid, Row, Col } from 'react-bootstrap';

it will generate something similarish to:

var reactBootstrap = require('react-bootstrap');
var Grid = reactBootstrap.Grid;
var Row = reactBootstrap.Row;
var Col = reactBootstrap.Col;

Some libraries, such as react-bootstrap and lodash, are rather large and pulling in the entire module just to use a few pieces would cause unnecessary bloat to your client optimized (webpack etc.) bundle. The only way around this is to use default style imports:

import Grid from 'react-bootstrap/lib/Grid';
import Row from 'react-bootstrap/lib/Row';
import Col from 'react-bootstrap/lib/Col';

But, the more pieces we need, the more this sucks. This plugin will allow you to pull in just the pieces you need, without a separate import for each item. Additionally, it can be configured to throw when somebody accidentally writes an import which would cause the entire module to resolve, such as:

import Bootstrap, { Grid } from 'react-bootstrap';
// -- or --
import * as Bootstrap from 'react-bootstrap';

Installation

npm install --save-dev swc-plugin-transform-import

Advanced Transformations

In cases where the provided default string replacement transformation is not sufficient (for example, needing to execute a RegExp on the import name), you may instead provide a path to a .js file which exports a function to run instead. Keep in mind that the .js file will be required relative from this plugin's path, likely located in /node_modules/babel-plugin-transform-imports. You may provide any filename, as long as it ends with .js.

.babelrc:

{
    "plugins": [
        ["transform-imports", {
            "my-library": {
                "transform": "../../path/to/transform.js",
                "preventFullImport": true
            }
        }]
    ]
}

/path/to/transform.js:

module.exports = function(importName) {
    return 'my-library/etc/' + importName.toUpperCase();
};

Options

| Name | Type | Required | Default | Description | | --- | --- | --- | --- | --- | | transform | string | yes | undefined | The library name to use instead of the one specified in the import statement. ${member} will be replaced with the member, aka Grid/Row/Col/etc. Alternatively, pass a path to a .js file which exports a function to process the transform (see Advanced Transformations) | | preventFullImport | boolean | no | false | Whether or not to throw when an import is encountered which would cause the entire module to be imported. | | skipDefaultConversion | boolean | no | false | When set to true, will preserve import { X } syntax instead of converting to import X. | | style | boolean or function | no | false | When set to true, will add side effect import of transformed path concatenated with /style. When set as a function, receive an argument as the transformed path, return the tramsformed style module path |